1. Field of the Invention
The present invention relates to oral compositions in the form of dentifrices and mouthwashes providing improved remineralization effects.
2. The Prior Art
In the mouth, there is a natural equilibrium between hydroxyapatite being dissolved from the enamel of teeth, on the one hand, and hydroxyapatite being formed on or in the teeth from substances occurring naturally in the saliva, on the other. The equilibrium is such that hydroxyapatite is dissolved, a cariogenic condition arises which is referred to as demineralization. If the equilibrium is such that hydroxyapatite is being formed in demineralized enamel, this is referred to as remineralization. By remineralization, pre-existing tooth decay and caries can be reduced or eliminated by natural means.
It has long been known that fluoride-providing compounds, even in low concentrations, are a safe and effective route for the promotion of the remineralization process. Although effective, excess amounts of fluoride releasing compounds have produced cosmetically objectionable fluorosis (mottling) in developing teeth in geographic areas in which the water supply contains relatively high levels of fluoride compounds.
Xylitol in combination with fluoride releasing compounds is known for the treatment of dental structures to provide prophylactic prevention of carious conditions, and/or remineralization of pre-existing carious conditions for example U.S. Pat. No. 5,089,255. EP Publication No. 0138705, discloses anticaries compositions containing xylitol and mixtures of at least two fluoride salts providing 2,000-20,000 ppm fluoride ion. EP Publication No. 0251146 discloses an oral composition having a dental plaque preventing activity containing a mixture of xylitol, a fluoride releasing compound, and one zinc ion releasing compound Xylitol alone, even at concentration levels of 10% by weight in the absence of fluoride releasing compounds, does not provide a remineralization effect comparable to that provided by fluoride releasing compounds. when incorporated in oral compositions.
Therefore there is a need in the art for a xylitol based oral composition, which is substantially free of fluoride ion releasing compounds which provides a remineralization effect comparable to that observed when used in combination with fluoride ion releasing compounds.